This invention relates generally to the field of medical compression and distraction devices in the field of bone fixation, repair and regeneration, and more particularly relates to such devices and methods utilized in mandibular and maxillary craniofacial repair, facial reconstruction, and treatment for congenital, developmental and traumatic defects.
It is often desirable or necessary to effect reconstruction or repair of the craniofacial bones defining the face of a person, such as the midface, the mandible and/or the maxilla. This need may arise from congenital conditions, developmental disorders or trauma. In many circumstances the abnormalities are corrected by first dividing a bone through osteotomy, i.e., cutting or fracturing a bone to create two segments separated by a gap or space. In some instances the bone segments will be shifted into the proper orientation and alignment, and then fixed in place relative to each other until bone growth across the gap results in the formation of a unitary bone member. In other instances it is necessary to lengthen the original bone member, in which case devices known as distractors are utilized. A distractor is a device that has affixation means, such as bone plates, that are joined to each of the bone segments on opposite sides of the osteotomy. The device further includes distraction means that allows the distance between the bone plates to be slowly increased over time, thereby allowing new bone growth to occur between the bone segments. The new bone growth increases in dimension until the proper bone length is achieved, at which time the distraction process is halted and the distractor is removed.
A typical example of this procedure is when the mandible or jawbone fails to fully develop in the anterior-posterior direction, a condition known as mandibular hypoplasia, which is manifested as a severely fore-shortened chin. To correct this anomaly, osteotomies are performed on each side of the mandible and a pair of distraction devices are affixed to the mandible. Extension of the distractors is performed in unison to lengthen the mandible until the desired position of the mandible relative to the midface is achieved. After sufficient regeneration and healing, the distractors are removed.
For another example, it is often desired to advance the midface or maxillary region relative to the jaw and skull to correct for maxillary hypoplasia, where the upper lip and/or nose are depressed relative to the remainder of the face structure. In this case the osteotomy may be performed across the maxilla to the nasal cavity, and a pair of distractors are affixed across the osteotomy gap, or an external distraction apparatus is mounted to the skull with affixed means to distract the anterior maxillary segment. Gradual extension of the distractors in unison advances the anterior maxillary segment relative to the posterior maxillary segments while bone regeneration fills in the osteotomy gap. When the proper position is achieved, distraction is halted. After sufficient regeneration and healing, the distractors are removed.
In certain situations it is necessary to advance both the mandible and the maxilla simultaneously to address the facial anomaly. To achieve this, osteotomies are performed on both the mandible and the maxilla, such that the anterior portions of the mandible and the maxilla are separated from the posterior portions. In one approach, four independent distractors are then affixed across the osteotomies, two on the maxillary segments and two on the mandibular segments. Distraction is performed as set forth above until the proper positions are reached for the mandible and the maxilla, and the distraction devices are removed after sufficient regeneration and healing. Alternatively, the upper and lower teeth can be wired together and a pair of distractors mounted to the mandible, such that advancement of the distractors simultaneously distracts both the anterior portion of the mandible and the anterior portion of the maxilla.
The known protocols for distraction of the mandible and maxilla possesses inherent problems. Affixation of the distractors involves invasive surgery, with multiple incisions and implantations of bone screws to affix the distractor bone plates being required. Thus, it is desirable to reduce the number of invasive procedures that must be done to address the craniofacial anomalies. It is often necessary to wire together or otherwise join the mandible to the maxilla such that normal opening of the jaw is precluded during the course of the treatment. This increases the risk of asphyxiation or choking, and thus it is desirable to provide a methodology and apparatus wherein the mandible can be quickly released from the maxilla if necessary.
It is an object of this invention to provide a craniofacial distraction device and method that addresses the problems set forth above in circumstances where simultaneous distraction of both the mandible and the maxilla are required. It is an object of this invention to provide a distractor device that may be affixed to both the mandible and the maxilla such that the anterior mandibular and maxillary segments are advanced simultaneously. It is an object of this invention to provide a distractor device that may be utilized in paired configuration, whereby only two distractors are necessary to achieve distraction of both sides of the mandible and maxilla, without need to wire together the upper and lower teeth. It is an object of this invention to provide a distractor device that may be converted to use as a single distractor, such that the device is adaptable for use with either the mandible or the maxilla. It is an object of this invention to provide a distractor device that provides a means for quick release of the superior components from the inferior components, whereby the release does not require damage or destruction of the distractor device such that the mandible can be freed from the maxilla and subsequently reunited. These objects as set forth above will be met as provided for in the disclosure to follow, and other objects not expressly set forth at this time will become apparent upon review of the disclosure to follow.